1. Field of the Invention
The present invention relates to a pump, and more particularly to an air pump that has a one-piece cylinder being structurally firm and providing excellent hermetic characteristics to prevent leakage and disassembly under high pressure.
2. Description of Related Art
Air pumps are popularly used in daily life to pump air into inflatable products such as basketballs and tyres.
With reference to FIG. 1, a conventional air pump has a cylinder and a piston assembly.
The cylinder has an air inlet, an air outlet, a body (120a) and a cap (110a) and a pedal base (130a).
The air inlet and outlet are defined in the cylinder.
The body (120a) has a chamber, an open top and an open bottom. The chamber has an inner sidewall.
The cap (110a) is mounted securely on the open top and has a through hole (111a) and an O-ring (141a). The through hole (111a) is defined through the cap (110a). The O-ring (141a) is mounted hermetically between the cap (110a) and the open top.
The pedal base (130a) is mounted securely on the open bottom and has an O-ring (142a) hermetically mounted between the pedal base (130a) and the open bottom.
The piston assembly has a shaft (210a), a handle (200a) and a piston (230a).
The shaft (210a) is mounted through the through hole (111a) of the cap (110a) in the chamber of the body (120a) and has a top end and a bottom end.
The handle (200a) is mounted on the top end of the shaft (210a). Reciprocally moving the handle (200a) drives the shaft (210a) to move up and down in the chamber.
The piston (230a) is mounted on the bottom end of the shaft (210a) and hermetically contacts the inner sidewall of the chamber of the body (120a). The piston (230a) is reciprocally driven to supply air into the chamber through the air inlet and pump air into an inflatable product through the air outlet.
However, the cylinder assembled by the separate components of the body (120a), cap (110a) and pedal base (130a) has following disadvantages.
1. When stored, separate components of the cylinder require management such as classification and indexing so increases storage costs.
2. Tolerances of the separate components are different so that precisely assembling the components into a cylinder is difficult and thus lowers quality and production rate of the air pump.
To overcome the shortcomings, the present invention provides an air pump with a one-piece cylinder to mitigate or obviate the aforementioned problems.